Polyether resins



Patented Feb. 27,

'uN1 Eo Sm-es- T'PAATENT, orrlca. a

a 2.1mm mm seams Henry 8.

1:, Del., aslignor Bothrcek. toE. I. du Pont de Nemours a Company,Wilmington, not. a corporation of Delaware No Application October 5,1038,

Serial N0. 233,479

a. 11 cums. 1(01. zoo-41) This invention relates to resinous materialsand more particularly to new and improved polyether resins obtained byreacting certain polyhydric phenols and organic polyhalides.

This case is a continuatlon-in-part of my application Serial No. 52,617,filed December 2, 1085.

, by their low softening points and by their non-'- thermohardeningproperties.

I In order to raise the softening points of these ether resins, it-hasbeen proposed in Patents 2,058,570 and 2,057,678 to use specific typesof polyhydric phenols as intermediates in the synthesis of the resins.These phenols or intermediates are relatively expensive and not readilyobtainable commercially. In addition, the resins described in theselatter two patents have also the disadvantage of not beingthermo-hardening.

An object of this invention is the preparation of new synthetic resins.A further object is a new process for making resins. A further object isthe manufacture of a modified form of ether resin which is free from thedisadvantages mentioned above. A still further object is the prepa-,ration of new synthetic resins which, although soluble in ordinarysolvents, are relatively inert to chemical influences and which possessthe property of becoming tough, insoluble and relatively high-softeningupon short baking at about 1100" C. 'The above and other. objectsappearing hereinafter are accomplished by reacting certain preformedpolyether resins in solution with small amounts of formaldehyde orsimilar aldehyde in the presence of a strong, non-oxidizing, inorganicacid catalyst. l The preparation of the polyether resins which form thestarting material for the present invention is fully described in theabove mentioned patents and is therefore but briefly referred to here.These synthetic resins, in which the new chemical union eflectedconsists essentially of ether linkages, are the reaction products ofsubstantially unpolymerizable polyhydric phenols and organicpolyhalides, free of ester groups,

whose halogen atoms are all attached to different carbon atoms which arein turn ioined, by single bonds only, to at least one carbon, anyvalences not satisfied by carbon being satisfied by hydrogen.- Thehalide is preferably a dihalide of the 6 formula x-(cnn m-O-(CH!) r-X,where x is a halogen and m and n are whole numbers greater than one. Anexample of a suitable phenol is di-(i-hydronphenyl)dimethylmethane, anda suitable polyhalide is p, p'-dichlorodiethyl ether. 10

The resins are best made by condensing the alkali or alkaline earthmetal polyhydric phenolate with the polyhalide.

The following is the preferred general method for'making these resins:The polyhydric phenol 1 is mixed with an'aqueous solution of thetheoretical or a slightly excess quantity of concentrated aqueous alkaliand heated ata relatively high 7 temperature, i. e., above C. andpreferably above (2., but below the decomposition temperatures of theingredients, with a substantially chemically equivalent amount of thepolyhalide. The apparatus preferably consists of a vessel fitted with athermometer, reflux condenser, and

a stirrer designed to sweep the sides and bottom. 25 ofthe vessel.Heating is continued. until the desired state of condensation isobtained or until as much of the phenol and halide are reacted aspossible. The phenol is largely reacted when the amount of acid' toneutralize a definite sample becomes essentially constant; where thetheoretical amount of alkali was used originally, the final product isnearly neutral. (This method of following the progress of theresiniflcation, however,

is sometimes only approximate since part of the alkali may be used up inthe hydrolysis of the polyhalide, a side reaction which does notcontribute to the'resinification.) When the halide is volatile, testscan be made for uncombined halide by distilling a few drops from thereaction 40.

vessel. If this distillate is cloudy. some of the halide is uncombinedand refluxing is continued.

when the distillate is clear, the water can be distilled oil! withoutloss of halide; this will then permit the use of higher temperatures inthe 45 later stages of'the reaction with a resultant decrease in time ofpreparation. Further heating after the distillate becomes clear isgenerally necessary inasmuch as this clear" point only shows thatessentially all the halide has been combined 50 by the elimination of atleast one of its halogen atoms, but not necessarily all of them. Thefinal reaction mass is very viscous, also opaque because of occludedsalt. When it has reached the desiredconsistency, the hot mass is pouredinto a i steam-jacketed Werner-Pfieiderer type mixer and washed withsmall portions of dilute hydrochloric acid, and finally with water toremove the salt.

The resin is then dried, either in vacuo or at atmospheric pressure, forseveral hours at temperatures above its melting point, e. g., in therange l150 C. Clear, tough resins are obtained whose hardness willdepend largely on the temperature, time of reaction, and certain otherdetails.

In order to-provide fool for reaction with aldehydes, it has beenproposed, as disclosed in the above mentioned patent, to introduce intothe ether resin a group, such as a sulfonamide group, known to bereactive with aldehydes; But the present discovery that, by the use ofan acid catalyst of the type given above, ether resins in general, andnot simply those containing groups of the mentioned type. wilLreact withformaldehyde and yield thermo-hardening resins, has not previously beendisclosed. The present process avoids the necessity of introducingextraneous groups which detract from the valuable propertiescharacterizing the ether resins. The new feature of carrying out thereaction with formaldehyde in the presence of certain acid catalysts,

. therefore, presents the advantage of producing thermo-hardening resinsfrom the more desirable ether resins which do not contain deleteriousforeign groups. It is for this reason that the ether resins of all theexamples given below, as will be seen from the chemical formula requiredby the compounds named, consist of carbon, hydrogen, and oxygen, theconstituents of the most valuable of the straight or unmodified etherresins. The oxygen contained in these resins is singly bonded oxygenonly.

Thefollowing resins are typical of those suitable for the practice ofthe present invention:

A resin useful in the practice of this invention may be made asindicated below:

and 18,3-

- P Di(4-hydroxyphenyl) dimethylmethane (M. P'. f 157 C.) Q56Dichlorodiethyl ether 286 Water Y 450 Sodium hydroxide (50%) 326 Theabove mixture is refluxed in an' atmosphere of nitrogen or water vaporwith stirring for to hours, or until a few drops of clear distillateshows that there is no remaining free halide. The water is distilled oi!over a period of 2 hours, the temperature finally being carried to.225-230 C. and maintained at this point for 12 hours. The mass is nowvery viscous and pasty. It is poured while hot into a steam-jacketedWerner- Pfleiderer mixer, washed three times with water, then with smallportions of dilute hydrochloric vention.

acid until the washings are acid to Congo red, and finally with wateragain 'until the washings are substantially free of chloride ion. Theproduct is thendried by heating in vacuo at 120-125 C. for 16 hours. andextremely tough, and is inert to acid, alkali, water and light. It isinsoluble in alcohol and aliphatic hydrocarbons, but soluble in toluol,

xylol and aromatic esters such as dibutyl phthalate.-. Filmsdry to anon-tacky condition in a very few minutes by simple evaporation ofsolvent; in this respect, the resin resembles cellulose derivatives. Theresin does not mix readily with oils andmost cellulose derivatives, butis compatible with benzyl cellulose. The resin does not heat- ;harden ordry by oxidation. It begins to soften at a comparatively lowtemperature, e. g., 40- 50 C. l

The polyether resins may also be made by any of the processes describedin the above mentioned patents, and with'any of the polyhydric phenolsand polyhalides mentioned in those patents. A particularly advantageousmethod consists in conducting the reaction in an alkaline medium towhich an amine has been added as a. catalyst.

As previously mentioned, the resins of this invention are'obtained byinteracting the polyether resins in solution with formaldehyde in thepresence of an acid catalyst such as dry hydrogen chloride. Nitrogen maythen be blown through the resulting solution of the reaction product toremove excess free hydrogen chloride. The resheated until reaction iscomplete, as judged by the attainment of the desired increase inviscosity. The reaction product is then cooled. If

desired, traces-of free hydrogen chloride remaining in the mixture maybe removed by blowing the slightly warm solution with nitrogen.

The following examples are illustrative of the methods which may be usedto carry out my in- Ezrample I Eleven hundred seventy-five (1175) gramsof a 40% solution in toluene of the polyether resin prepared asdescribed above were placed in a 2- liter flask equipped with a mercuryseal stirrer, V condenser, and inlet tube for EC] gas. The contents ofthe vessel'were brought to about 95 C. and 4.7 grams (1%) cfparaformaldehyde were added. Dry hydrogen chloride gas was then passedinto the reaction vessel during a period of one-half hour. At the endof' this time, the solution was cooled quickly in an ice bath, thenblown with nitrogen for 1.5 hours to remove traces of HCl. The productwas a clear homogeneous solution, very much more viscous than theoriginal. Thus a 40% solution in tolueneof the treated resin had aviscosity of about 98 poises as compared wtih 5 poises for the originalsolu-- tion. Films of the resin flowed on glass plates and air-dried fora short time, and then heated for 10 minutes at 125 C., were renderedinsolu-' ble in toluene. The softening point of the hardened films wasabout 85C., as compared with 7 The resin is clear, pale-colored 5 a191,:45 C. for the original resin. The dried films both before and afterhardening werelight-colored. tough. and flexible.

It will be observed from the above example that the resin preparedaccording to this invention was heat-hardening, and after hardening hada higher softening point than thenon-heathardening polyether resin fromwhich it was derived. It is to be noted that I employ the termshardenable, heat-harden," etc, to mean that the softening temperature-ofthe resin is appreciably increased by the application of heat, but

not to mean that the resin is necessarily rendered convertible by heatto the infusible stage. In

general, it is also true that the' present formaldehydrous or' not, but,if the latter, the reaction proceeds rather slowly unless, as indicatedin the following examples, a blending agent such as glacial acetic acidis added to homogenize the.

solution containing formaldehyde, acid and resin.

Example II One hundred (100) grams of a 40% solutio in toluene of thepolyether resin prepared as described above, 50 grams of glacial aceticacid, 3'

grams of 37% aqueous formaldehyde solution, and 5 grams of concentratedhydrochloric acid were placed in a 500 cc. round bottom flask equippedwith stirrer, etc., as in Example I, and the mixture was heated at about90 C. with stirring for 1.5 hours. A cooled sample of the reactionmixture had much higher viscosity than that of the original mixture, andafter two hours heating the reaction mixture was a jelly-like mass. nevaporation of the solvent from the mixture, a clear resin was obtained,soluble in toluene. On baking the resin for 10 minutes at 120 C. theresin became insoluble in toluene.

Example In One hundred (100) grams of a 40% toluene solution of thepolyether resin used in Example II, 50 grams o f'glacial acetic acid, 3grams of concentrated sulphuric acid, and 0.5 gram of paraformaldehydewere heated as described in Example 11. After minutes heating at 90 C.the viscosity of the reaction mixture had increased greatly, and themixture was cooled. A sample of the cooled mixture was heated in avacuum ovenfor a few minutes to remove the acetic acid. The resin wasfound to besoluble in toluene but films of the solution dried at 120.

C. for 5 minutes became insoluble in toluene.

The invention described herein is usually most satisfactorily carriedout with formaldehyde in an 'amount of about 1% of the resin. As a rule,the

amount of formaldehyde orparaformaldehyde used is from 0.01 77J to10.0%. However, the ratio which can be used to produce soluble'resinsdepends somewhat upon the duration of heating and upon other factors aswell as upon the amount of formaldehyde. Thus, reaction mixturescontaining the very small amounts of formaldehyde just mentioned willgel and the resulting resins will:be insoluble if the heating is carriedtoo far.

7. 011 the other hand, larger amounts of formaldeeral suitable.

hyde can be used without producing insoluble resins if the reaction isallowed to proceed only a comparatively short time Reaction mixturescontaining 20% of formaldehyde (based on the weight of the body of theresin) gel, and the resin becomes insoluble very quickly. The insolubleheat-hardening resins thus made by using the larger amounts offormaldehyde or by using .longer heating times are, however, useful forsome purposes, such as molding.

Temperatures suitable for carrying out this invention cannot be setdefinitely because operable ranges will depend on the amount of formaldehyde employed, larger amounts of the latter requiring a lowertemperature and time of treatment. Asa rule, however, byproperly'adjusting the amount of formaldehyde and by proper selection ofsolvent it is generally possible to operate within the temperature rangeof 40-l00 C.

.Temperatures outside this range, however, are

not precluded. For instance, it is possible by application of pressureand use of small amounts of formaldehyde (e.-g .,'1ess than 1.0%) tooperate at temperatures upto 140 C. I,

Variousnon-reactive solvents such as benzene,

p-cymene, mesitylene, and xylene may replace wholly or in part thetoluene of the examples. Mononuclear aromatic hydrocarbons are in gen-Pressures above atmospheric may be used.

Some of the formaldehyde-treated resins of this invention have atendency to be converted to insoluble products even in solution at roomtemperature.

cyclohexane, or a mixture of di(4-hydroxy- Thus, if a resin preparedfrom di-' chlorodiethyl ether and 1,1-di(4-hydroxyphenyl) phenyl)dimethylmethane therewith, is treated with formaldehyde as in Example I,the resulting resin solution thickens gradually even at roomtemperature, an insoluble gel being eventually formed." This effect istroublesome if it is desired to store the resin for any length of time.The

diflicultymay be avoided conveniently by the ad- I dition of smallamounts of ammonia to the solution, preferably by passing in ammonia gaswith stirring, or by shaking with aqueous ammonia. Other alkalinereagents may be used, for example, alkali carbonate solutions, gaseousmethylamine, etc. The action of the ammonia or other alkaline material,in' retarding the hardening process is probably due to neutralization oftraces of acid catalyst.

Resins stabilized by ammonia as described are rendered permanentlyfusible and cannot be hardened even on extended baking at elevatedtemperatures. The stabilized resins still possess the improved softeningpoint of the unstab'ilized resins. and the method thus oflers a meansfor nullifying the heat-hardening properties of the formaldehyde-treatedresins without loss of the .valuable increase in softening temperature.

' It is to be observed that the process for making the resins describedherein has no relation to the phenol-aldehyde resin forming. reaction.In the present instance the reaction for producing the initial etherresin is not one of the polymeriza tion of a polymerizable phenol orphenol alcohol -or other intermediate obtained by the interaction .ofphenol and aldehyde, but is the product obtained bythe etherification ofpolyhydric pheent invention involves the reaction of a resin of thementioned specific chemical constitution with formaldehyde, and not thereaction of phenols or of non-resinous bodies with aldehydes as is the II nols by certain polyhalides. Then, also, the prescase in theproduction of phenol-aldehyde resins. Furthermore, the products obtainedby the practice of the present invention are wholly different inproperties from the phenol-aldehyde resins. The resins of this inventionare constituted largely of ether linkages and retain all the desirableproperties of the ether resins in as much as the subsequent formaldehydetreatment does not detract from these properties and confers additionalfeatures of elevating the softening points and of producinghardenability. Additionally, the different nature of the presentproducts and of i the reaction involved in their manufacture is ins arealso useful for coating paper, cloth, and

other flexible sheet materials. They may be used for all purposes forwhich thermo-hardening resins are ordinarily used, and in this respectthey possess a distinct advantage over the untreated polyether resinsfrom which they are derived.

The process for preparing the resins described herein is highlyadvantageous in that it opens a simple new way to obtain high-softening,tough polyether resins, and in that it avoids'the necessity of using thespecial types of relatively unavailable, expensive intermediatesheretofore necessary to prepare polyether resins having such properties.It further opens a way readily to transform the thermoplastic resinsdescribed in the patents mentioned above into thermo-hardening resins of(when hardened) higher softening points, and makes it possible for theseresins to compete with ordinary phenol-formaldehyde resins for many orall of the uses to which the latter may be put. All of these advantagesare obtained without sacrificing the desirable properties of theoriginal polyether resins, i. e., toughness, durability, chemicalinertness, and resistance to light; properties which are by no means vcharacteristic of the well-known thermo hardening phenolic or urearesins. For instance, the resins prepared according to this inventionare tough, inert to chemical influences to a remarkable extent, and havethe other desirable properties described in the mentioned patents. Sincethe resins claimed herein are heat-hardening and have a highervsoftening temperature and decreased solubility after baking, they have abroad er field of usefulness than the untreated poly.- ether resins fromwhich they are derived. The resins described herein are then useful forpurposes in which ordinary heat-hardening resins have hitherto beenexclusively used. Yet the resins of this invention have, until they areheathardened, substantially the same desirable solubilitycharacteristics as do the original polyether resins from which they arederived. The interaction of polyether resins with the amounts offormaldehyde described herein with the production of the markeddifferences in softening point and in thermo-hardening properties isquiteremarkable. The simplicity andlow cost of the present 'process aredistinct advantages of this invention. d

As many apparently widely different embodi-' ments of this invention maybe made without departing from the spirit and scope thereof, it is to beunderstood that I do not limit myself to the specific embodimentsthereof except as defined in the appended claims. 7

I claim:

1. A process which comprises reacting with formaldehyde, in the presenceof an acid catalyst,

a thermoplastic resin consisting essentially of ether linkages until athermo-hardening soluble resin having a softening point substantiallyhigher than said thermoplastic resin is obtained,

said thermoplastic ether resin consisting of carbon, hydrogen and oxygenand being the reaction product of a substantially unpolymerizablemonomeric polyhydric phenol and'an organic polyhalide, free of estergroups, whose halogen atoms are all attached to different carbon atomswhich are in turn joined, by single bonds only, to at least one carbon,any valences not satisfied by carbon being satisfied by hydrogen.

2. A process which comprises reacting a therrmoplastic resin consistingessentially of ether linkages with formaldehyde in the presence of anacid catalyst and in the presence of a mononucleararomatidhydrocarbonsolvent for the resin until a thermo-hardening soluble resin having a'softening point substantially higher than said- 7 thermoplastic resin isobtained, said thermoplastic ether resin being the reaction product of asubstantially unpolymerizable monomeric polyhydric groups, whose halogenatoms'are all attached to difl'erent carbon atoms which are in turnjoined, bysingle bonds only, to at least one carbonjany valences notsatisfied by carbon being satisfied by hydrogen.

3. A process ,which comprises reacting with formaldehydain the presenceof gaseous hydro .phenol and an organic polyhalide, free of ester 7 genchloride, a thermoplastic resin consisting I essentially of etherlinkages until a thermohardening soluble resin having a softeningpoint'substantially higher than said thermoplastic resin is obtained,said thermoplastic ether resin being the reaction product of asusbtantially unpolymerizable monomeric polyhydric phenol and an organicpolyhalide, free of ester groups, whose halogen atoms are all attachedto different carbon halogen atoms are all attached to diiferent carbonatoms which are in turn joined, by single bonds only, to at least onecarbon, any valences not satisfied by carbon being satisfied byhydrogen.

5. The process set forth'in claim 1' in which the formaldehyde isemployed in-an amount of 0.01% to 10% of said thermoplastic resin. 6.The process set forth in claim 1 in which the reacting of saidthermoplastic resin and formaldehyde is at a temperature of 40 C. to C.

"7. A soluble thermo-hardening resin comprising the reaction product offormaldehyde with a thermoplastic resin consisting essentially of ethergroups, said thermoplastic ether resin consisting of carbon, hydrogenand oxygen and being the reaction product of a substantiallyunpolymerizable monomeric polyhydric phenol and an .organic' polyhalide,free of ester groups, whose halogen atoms are all attached to differentcarbon atoms which are in turn joined, by single bonds only, to at leastone carbon, any valences not satisfied by carbon being satisfied byhydrogen.

8. The process set forth in claim 1 in which said I polyhalide is of theformula xwmmoxcmhx where X is halogen and mand n are greater than 1.

9. The soluble theme-hardening resin set forth in claim 7 in which saidpolyhalide is of the formula x.(CH2)m-0-(CH2) ,.x where X is halogen andm and n are greater than 1.

10. The thermo-hardening product obtained by treating with ammonia thereaction product of formaldehyde in the presence of acid catalyst with athermoplastic resin consisting essentially of ether linkages, said resinbeing the reaction product of a substantially unpolymerizable mono--meric polyhydric phenol and an organic polyhalide, free of estergroups, whose halogen atoms are ether.

HENRY S.

